Real mirror = fps hit + lots of work.
MFD rear view = no added fps hit, not difficult to do.
Does the real Blackshark have a rear-view camera? Probably not. Could one be installed? Quite easily, since power and a monitor are already in place. Mount the camera, run the video coax through a video switch along with the regular llltv video feed, then to the MFD input, and voila, rear-view camera.